Thermally primed hydrogen-producing fuel cell system

ABSTRACT

Thermally primed fuel processing assemblies and hydrogen-producing fuel cell systems that include the same. The thermally primed fuel processing assemblies include at least one hydrogen-producing region housed within an internal compartment of a heated containment structure. In some embodiments, the heated containment structure is an oven. In some embodiments, the compartment also contains a purification region and/or heating assembly. In some embodiments, the containment structure is adapted to heat and maintain the internal compartment at or above a threshold temperature, which may correspond to a suitable hydrogen-producing temperature. In some embodiments, the containment structure is adapted to maintain this temperature during periods in which the fuel cell system is not producing power and/or not producing power to satisfy an applied load to the system. In some embodiments, the fuel cell system is adapted to provide backup power to a power source, which may be adapted to power the containment structure.

FIELD OF THE DISCLOSURE

The present disclosure is directed generally to hydrogen-producing fuelcell systems, and more particularly, to hydrogen-producing fuelprocessing systems with thermally primed hydrogen-producing regions.

BACKGROUND OF THE DISCLOSURE

As used herein, a fuel processing assembly is a device or combination ofdevices that produces hydrogen gas from one or more feed streams thatinclude one or more feedstocks. Examples of fuel processing assembliesinclude steam and autothermal reformers, in which the feed streamcontains water and a carbon-containing feedstock, such as an alcohol ora hydrocarbon. Fuel processors typically operate at elevatedtemperatures. In endothermic fuel processing reactions, such as in steamreforming fuel processing assemblies, the heat required to heat at leastthe hydrogen-producing region of the fuel processing assembly to, andmaintain the region at, a suitable hydrogen-producing temperature needsto be provided by a heating assembly, such as a burner, electricalheater or the like. When burners are used to heat the fuel processor,the burners typically utilize a combustible fuel stream, such as acombustible gas or a combustible liquid.

In a hydrogen-producing fuel processing assembly that utilizes a steamreformer, or steam reforming region, hydrogen gas is produced from afeed stream that includes a carbon-containing feedstock and water. Steamreforming is performed at elevated temperatures and pressures, and asteam reformer typically includes a heating assembly that provides heatfor the steam reforming reaction. Illustrative but not exclusive uses ofthe heat include maintaining the reforming catalyst bed at a selectedreforming temperature, or temperature range, and vaporizing a liquidfeed stream prior to its use to produce hydrogen gas. One type ofheating assembly is a burner, in which a combustible fuel stream iscombusted with air. In a hydrogen-producing fuel processing assemblythat utilizes an autothermal reformer, or autothermal reforming region,hydrogen gas is produced from a feed stream that includes acarbon-containing feedstock and water, which is reacted in the presenceof air. Steam and autothermal reformers utilize reforming catalysts thatare adapted to produce hydrogen gas from the above-discussed feedstreams when the hydrogen-producing region is at a suitablehydrogen-producing temperature, or within a suitable hydrogen-producingtemperature range. The product hydrogen stream from thehydrogen-producing region may be purified, if needed, and thereafterused as a fuel stream for a fuel cell stack, which produces an electriccurrent from the product hydrogen stream and an oxidant, such as air.This electric current, or power output, from the fuel cell stack may beutilized to satisfy the energy demands of an energy-consuming device.

A consideration with any hydrogen-producing fuel cell system is the timeit takes to begin generating an electric current from hydrogen gasproduced by the fuel cell system after there is a need to begin doingso. In some applications, it may be acceptable to have a period of timein which there is a demand, or desire, to have the fuel cell systemproduce a power output to satisfy an applied load, but in which thesystem is not able to produce the power output. In other applications,it is not acceptable to have a period where the applied load from anenergy-consuming device cannot be satisfied by the fuel cell system eventhough there is a desire to have this load satisfied by the system. Asan illustrative example, some fuel cell systems are utilized to providebackup, or supplemental power, to an electrical grid or other primarypower source. When the primary power source is not able to satisfy theapplied load thereto, it is often desirable for the backup fuel cellsystem to be able to provide essentially instantaneous power so that thesupply of power to the energy-consuming devices is not interrupted, ornot noticeably interrupted.

Fuel cells typically can begin generating an electric current within avery short amount of time after hydrogen gas or another suitable fueland an oxidant, such as air, is delivered thereto. For example, a fuelcell stack may be adapted to produce an electric current within lessthan a second after the flows of hydrogen gas and air are delivered tothe fuel cells in the fuel cell stack. Inclusive of the time required toinitiate the delivery of these streams from a source containing thehydrogen gas and air, the time required to produce the electric currentshould still be relatively short, such as less than a minute. However,hydrogen-producing fuel cell systems that require the hydrogen gas tofirst be produced, and perhaps purified, prior to being utilized togenerate the desired power output take longer to generate this poweroutput. When the fuel processing assembly is already at a suitablehydrogen-producing temperature, the fuel cell system may be able toproduce the desired power output from hydrogen gas generated by the fuelprocessing assembly within a few minutes, or less. However, when thehydrogen-producing fuel processor of the fuel cell system's fuelprocessing assembly is not already at a desired hydrogen-producingtemperature, the required time will be much longer. For example, whenstarted up from an ambient temperature of 25° C., it may take thirtyminutes or more to properly start up the fuel processing assembly and toproduce the desired power output from hydrogen gas produced by the fuelprocessing assembly.

Conventionally, several different approaches have been taken to providehydrogen-producing fuel cell systems that can satisfy an applied loadwhile the associated hydrogen-producing fuel processing assembly isstarted up from its off, or unheated and inactive, operating state,heated to a suitable hydrogen-producing temperature, and thereafterutilized to produce and optionally purify the required hydrogen gas toproduce a power output to satisfy the applied load. One approach is toinclude one or more batteries or other suitable energy storage devicesthat may be used to satisfy the applied load until the fuel cell systemcan produce a sufficient power output to satisfy the applied load.Typically, this approach also requires that the fuel cell system includesuitable chargers to recharge the batteries during operation of the fuelcell system. This approach is effective, especially for lower powerdemands of 1 kW or less, so long as the weight and size requirements ofthe battery, or batteries, is acceptable. In portable fuel cell systemsand fuel cell systems that are designed to satisfy greater appliedloads, such as loads of 10 kW or more, it may not be practical toutilize batteries to satisfy an applied load for the time required forthe fuel processing assembly to be started up. Another approach is forthe fuel processing assembly to include a hydrogen storage device thatis sized and otherwise configured to store a sufficient amount ofhydrogen gas to supply the fuel cell stack while the fuel processingassembly is started up. Typically, this approach also requires that thefuel cell system include suitable compressors and other control andregulation structure to recharge the storage device. This approach isalso effective, but requires that the space, additional equipment andexpense of including the storage device and associated components isacceptable.

In some applications, it may be desirable to be able to produce adesired power output from hydrogen gas produced by the fuel processingassembly of a hydrogen-producing fuel cell system without requiringeither stored hydrogen or stored power to be used to satisfy the appliedload while the fuel processing assembly is started up from an inactive,or off, operating state and heated to a suitable hydrogen-producingtemperature.

SUMMARY OF THE DISCLOSURE

The present disclosure is directed to thermally primed fuel processingassemblies and to hydrogen-producing fuel cell systems that include thesame. The thermally primed fuel processing assemblies include at leastone hydrogen-producing region, such as may be adapted to producehydrogen gas by a steam reforming or autothermal reforming processutilizing a suitable reforming catalyst. At least the hydrogen-producingregion is housed within an internal compartment of a heated containmentstructure. In some embodiments, the containment structure may be aheated and insulated containment structure. In some embodiments, theheated containment structure is an oven. In some embodiments, at leastone purification region and/or heating assembly is contained within theinternal compartment with the hydrogen-producing region. In someembodiments, the containment structure is adapted to heat and maintainthe internal compartment at or above a threshold temperature, or withina selected temperature range, which in some embodiments may correspondto a suitable hydrogen-producing temperature or temperature range forthe hydrogen-producing region. In some embodiments, the containmentstructure is adapted to maintain the internal compartment at thistemperature, or temperature range, during periods in which the fuel cellsystem is not producing a power output and/or not producing a poweroutput to satisfy an applied load to the system. In some embodiments,the fuel cell system is adapted to provide backup, or supplemental,power to a primary power source that is adapted to provide power to atleast one energy-consuming device, and in some embodiments, the primarypower source is further adapted to provide power to the containmentstructure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of a thermally primed hydrogen-producing fuelcell system according to the present disclosure.

FIG. 2 is a schematic view of a thermally primed hydrogen-producing fuelprocessing assembly according to the present disclosure.

FIG. 3 is a fragmentary schematic view of another thermally primedhydrogen-producing fuel processing assembly according to the presentdisclosure.

FIG. 4 is a fragmentary schematic view of another thermally primedhydrogen-producing fuel processing assembly according to the presentdisclosure.

FIG. 5 is a schematic view of portions of another thermally primedhydrogen-producing fuel processing assembly according to the presentdisclosure FIG. 6 is a schematic view of another thermally primedhydrogen-producing fuel processing assembly according to the presentdisclosure.

FIG. 7 is a schematic view of a thermally primed hydrogen-producing fuelcell system according to the present disclosure.

FIG. 8 is a schematic view of a thermally primed hydrogen-producing fuelcell system according to the present disclosure, as well as anenergy-consuming device and a primary power source that is normallyadapted to provide power to the energy-consuming device.

DETAILED DESCRIPTION AND BEST MODE OF THE DISCLOSURE

A thermally primed fuel processing assembly is shown in FIG. 1 and isindicated generally at 10. Thermally primed fuel processing assembly 10includes a thermally primed fuel processor 12 that is adapted to producea product hydrogen stream 14 containing hydrogen gas, and preferably atleast substantially pure hydrogen gas, from one or more feed streams 16.Feed stream 16 includes at least one carbon-containing feedstock 18, andmay include water 17. Fuel processor 12 is any suitable device, orcombination of devices, that is adapted to produce hydrogen gas fromfeed stream(s) 16. Accordingly, fuel processor 12 includes ahydrogen-producing region 19, in which a hydrogen gas is produced usingany suitable hydrogen-producing mechanism(s) and/or process(es). Theproduct hydrogen stream may be delivered to a fuel cell stack 40, whichis adapted to produce an electric current, or power output, 41 fromhydrogen gas and an oxidant, such as air. An air stream is illustratedat 43 in FIG. 1 and may be delivered to the fuel cells in the stack viaany suitable mechanism or process. Systems according to the presentdisclosure that include at least one fuel cell stack and at least onethermally primed fuel processing assembly that is adapted to producehydrogen gas for the at least one fuel cell stack may be referred to asthermally primed hydrogen-producing fuel cell systems. Although a singlefuel processor 12 and/or a single fuel cell stack 40 are shown in FIG.1, it is within the scope of the disclosure that more than one of eitheror both of these components, and/or subcomponents thereof, may be used.

Thermally primed fuel processing assembly 10 includes ahydrogen-producing region 19 that is housed within a heated containmentstructure, or heated containment assembly, 70 and which is adapted toproduce hydrogen gas from the one or more feed streams by utilizing anysuitable hydrogen-producing mechanism(s). As discussed in more detailherein, containment structure 70 defines an internal compartment 72 intowhich at least the hydrogen-producing region of the fuel processingassembly is located. The containment structure includes a heatingassembly that is adapted to heat and maintain the internal compartment,and structures contained therewithin, to a threshold temperature, ortemperature range. This threshold temperature, or temperature range maycorrespond to a suitable hydrogen-producing temperature, or temperaturerange, for the fuel processing assembly to produce hydrogen gas in itshydrogen-producing region. The containment structure may also bereferred to as a heated containment system, and/or a positively heatedthermal reservoir that contains at least the hydrogen-producing regionof the fuel processing assembly.

Feed stream(s) 16 may be delivered to the hydrogen-producing region ofthermally primed fuel processor 12 via any suitable mechanism. While asingle feed stream 16 is shown in solid lines in FIG. 1, it is withinthe scope of the disclosure that more than one stream 16 may be used andthat these streams may contain the same or different feedstocks. This isschematically illustrated by the inclusion of a second feed stream 16 indashed lines in FIG. 1. When feed stream 16 contains two or morecomponents, such as a carbon-containing feedstock and water, thecomponents may be delivered in the same or different feed streams. Forexample, when the fuel processor is adapted to produce hydrogen gas froma carbon-containing feedstock and water, these components are typicallydelivered in separate streams, and optionally (at least until bothstreams are vaporized or otherwise gaseous), when they are not misciblewith each other, such as shown in FIG. 1 by reference numerals 17 and 18pointing to different feed streams. When the carbon-containing feedstockis miscible with water, the feedstock is typically, but is not requiredto be, delivered with the water component of feed stream 16, such asshown in FIG. 1 by reference numerals 17 and 18 pointing to the samefeed stream 16. For example, when the fuel processor receives a feedstream containing water and a water-soluble alcohol, such as methanol,these components may be premixed and delivered as a single stream.

In FIG. 1, feed stream 16 is shown being delivered to fuel processor 12by a feedstock delivery system 22, which schematically represents anysuitable mechanism, device or combination thereof for selectivelydelivering the feed stream to the fuel processor. For example, thedelivery system may include one or more pumps that are adapted todeliver the components of stream 16 from one or more supplies.Additionally, or alternatively, feedstock delivery system 22 may includea valve assembly adapted to regulate the flow of the components from apressurized supply. The supplies may be located external of the fuelprocessing assembly, or may be contained within or adjacent theassembly. When feed stream 16 is delivered to the fuel processor in morethan one stream, the streams may be delivered by the same or separatefeedstock delivery systems.

Hydrogen-producing region 19 may utilize any suitable process ormechanism to produce hydrogen gas from feed stream(s) 16. The outputstream 20 from the hydrogen-producing region contains hydrogen gas as amajority component. Output stream 20 may include one or more additionalgaseous components, and thereby may be referred to as a mixed gas streamthat contains hydrogen gas as its majority component. As discussed,examples of suitable mechanisms for producing hydrogen gas from feedstream(s) 16 include steam reforming and autothermal reforming, in whichreforming catalysts are used to produce hydrogen gas from a feed stream16 containing a carbon-containing feedstock 18 and water 17. Examples ofsuitable carbon-containing feedstocks 18 include at least onehydrocarbon or alcohol. Examples of suitable hydrocarbons includemethane, propane, natural gas, diesel, kerosene, gasoline and the like.Examples of suitable alcohols include methanol, ethanol, and polyols,such as ethylene glycol and propylene glycol.

Steam reforming is one example of a hydrogen-producing mechanism thatmay be employed in hydrogen-producing region 19 in which feed stream 16comprises water and a carbon-containing feedstock. In a steam reformingprocess, hydrogen-producing region 19 contains a suitable steamreforming catalyst 23, as indicated in dashed lines in FIG. 1. In suchan embodiment, the fuel processor may be referred to as a steamreformer, hydrogen-producing region 19 may be referred to as a reformingregion, and output, or mixed gas, stream 20 may be referred to as areformate stream. As used herein, reforming region 19 refers to anyhydrogen-producing region utilizing a steam reforming hydrogen-producingmechanism. Examples of suitable steam reforming catalysts includecopper-zinc formulations of low temperature shift catalysts and achromium formulation sold under the trade name KMA by Süd-Chemie,although others may be used. The other gases that may be present in thereformate stream include carbon monoxide, carbon dioxide, methane,steam, and/or unreacted carbon-containing feedstock.

Steam reformers typically operate at temperatures in the range of 200°C. and 900° C., and at pressures in the range of 50 psi and 300 psi,although temperatures and pressures outside of this range are within thescope of the disclosure. When the carbon-containing feedstock ismethanol, the hydrogen-producing steam reforming reaction will typicallyoperate in a temperature range of approximately 200-500° C. Illustrativesubsets of this range include 350-450° C., 375-425° C., and 375-400° C.When the carbon-containing feedstock is a hydrocarbon, ethanol, or asimilar alcohol, a temperature range of approximately 400-900° C. willtypically be used for the steam reforming reaction. Illustrative subsetsof this range include 750-850° C., 725-825° C., 650-750° C., 700-800°C., 700-900° C., 500-800° C., 400-600° C., and 600-800° C. It is withinthe scope of the present disclosure for the hydrogen-producing region toinclude two or more zones, or portions, each of which may be operated atthe same or at different temperatures. For example, when thehydrogen-production fluid includes a hydrocarbon, in some embodiments itmay be desirable to include two different hydrogen-producing portions,with one operating at a lower temperature than the other to provide apre-reforming region. In such an embodiment, the fuel processing systemmay alternatively be described as including two or morehydrogen-producing regions. Feed stream 16 is typically delivered toreforming region 19 of fuel processor 12 at a selected pressure, such asa pressure within the illustrative pressure range presented above.Thermally primed fuel processing assemblies according to the presentdisclosure may therefore be adapted to maintain at least thehydrogen-producing region of the fuel processor at or above a thresholdhydrogen-producing temperature that corresponds to one of theabove-presented illustrative temperatures, and/or within a selectedthreshold temperature range that corresponds to one of theabove-presented illustrative temperature ranges.

Another suitable process for producing hydrogen gas in thehydrogen-producing region 19 of thermally primed fuel processor 12 isautothermal reforming, in which a suitable autothermal reformingcatalyst is used to produce hydrogen gas from water and acarbon-containing feedstock in the presence of air. When autothermalreforming is used, the thermally primed fuel processor further includesan air delivery assembly 68 that is adapted to deliver an air stream tothe hydrogen-producing region, as indicated in dashed lines in FIG. 1.Thermally primed fuel processing assemblies may be adapted to maintainhydrogen-producing regions that utilize an autothermal reformingreaction at one of the above-presented illustrative temperatures, ortemperature ranges, discussed with respect to hydrogen-producing steamreforming reactions. Autothermal hydrogen-producing reactions utilize aprimary endothermic reaction that is utilized in conjunction with anexothermic partial oxidation reaction that generates heat within thehydrogen-producing region upon initiation of the initialhydrogen-producing reaction. Accordingly, even though autothermalhydrogen-producing reactions include an exothermic reaction, a needstill exists to initially heat the hydrogen-producing region to at leasta minimum suitable hydrogen-producing temperature.

The product hydrogen stream 14 produced by the fuel processing assemblymay be delivered to a fuel cell stack 40. A fuel cell stack is a devicethat produces an electrical potential from a source of protons, such ashydrogen gas, and an oxidant, such as oxygen gas. Accordingly, a fuelcell stack may be adapted to receive at least a portion of producthydrogen stream 14 and a stream of oxygen (which is typically deliveredas an air stream), and to produce an electric current therefrom. This isschematically illustrated in FIG. 1, in which a fuel cell stack isindicated at 40 and produces an electric current, or power output, whichis schematically illustrated at 41. Fuel cell stack 40 contains at leastone, and typically multiple, fuel cells 44 that are adapted to producean electric current from an oxidant, such as air, oxygen-enriched air,or oxygen gas, and the portion of the product hydrogen stream 14delivered thereto. The fuel cells typically are joined together betweencommon end plates 48, which contain fluid delivery/removal conduits,although this construction is not required to all embodiments. Examplesof suitable fuel cells include proton exchange membrane (PEM) fuel cellsand alkaline fuel cells. Others include solid oxide fuel cells,phosphoric acid fuel cells, and molten carbonate fuel cells.

The electric current, or power output, 41 produced by stack 40 may beused to satisfy the energy demands, or applied load, of at least oneassociated energy-consuming device 46. Illustrative examples of devices46 include, but should not be limited to, tools, lights or lightingassemblies, appliances (such as household or other appliances),households or other dwellings, offices or other commercialestablishments, computers, signaling or communication equipment, etc.Similarly, fuel cell stack 40 may be used to satisfy the powerrequirements of fuel cell system 42, which may be referred to as thebalance-of-plant power requirements of the fuel cell system. It shouldbe understood that device 46 is schematically illustrated in FIG. 1 andis meant to represent one or more devices, or collection of devices,that are adapted to draw electric current from, or apply a load to, thefuel cell system.

As discussed, heated containment structure 70 is adapted to heat andmaintain at least the hydrogen-producing region of the thermally primedfuel processor at a suitable hydrogen-producing temperature, such as atone of the illustrative temperatures discussed above and/or +/−25° C. ofthese illustrative temperatures. An illustrative example of a suitablecontainment structure 70 is schematically illustrated in FIG. 2. Asshown, the containment structure defines an enclosure 84 containinginternal compartment 72, which is sized to receive, or house, at leastthe hydrogen-producing region of fuel processor 12. The enclosureincludes walls 86, which preferably include internal surfaces 88 thatdefine an at least substantially, if not completely, closed boundaryaround the internal compartment. It is within the scope of the presentdisclosure that walls 86 may have the same or different thicknesses,sizes, shapes, and the like. Similarly, it is not required that theenclosure have a rectilinear configuration, with FIG. 2 merely intendedto provide an illustrative schematic example.

The walls and/or other portions of enclosure 86 preferably are insulatedto reduce the thermal load, or energy demand, to heat and maintain theinternal compartment at the selected temperature. Although not required,it is within the scope of the present disclosure that the enclosure,such as walls 86, is/are sufficiently insulated that the exteriorsurface 90 thereof is maintained at or below a threshold externaltemperature while the internal compartment is maintained at one of thesuitable threshold hydrogen-producing temperatures discussed herein.Illustrative, non-exclusive examples of suitable threshold externaltemperatures include temperatures of less than 100° C., thresholds ofless than 75° C., less than 50° C., and less than 25° C. As discussed,these external temperatures are not required, and the exterior of theenclosure may be at temperatures that exceed these illustrative exampleswithout departing from the scope of the present disclosure.

It is within the scope of the present disclosure that the enclosure 84may include one or more vents or other air-circulation passages. It isalso within the scope of the present disclosure that the only fluidpassages between the internal compartment and exterior of the enclosureis through defined inlet and outlet conduits, or ports, such as todeliver feed stream(s) to the hydrogen-producing region, to withdraw thehydrogen-containing stream(s) from the enclosure, and/or to deliver airto into the compartment and to withdraw exhaust from the enclosure. Thisis somewhat schematically illustrated in FIG. 2, in which a feed streamport is indicated at 92, a product hydrogen port is indicated at 94, anair inlet port is indicated at 96, and an exhaust port is indicated at98. More than one of the illustrated examples of possible ports may beincluded in any containment structure according to the presentdisclosure. Similarly, the structure may include one or more ports inaddition to, or instead of, one or more of the illustrative portsdescribed above.

When the fluid streams that are delivered into or withdrawn from aparticular structure within the internal compartment, such as instead ofthe internal compartment generally, the ports may be associated with oneor more fluid conduits 100 that define prescribed flow paths for thefluids within the compartment. For example, feed port 92 includes afluid conduit that delivers the feed stream to the hydrogen-producingregion. This conduit may define or otherwise form at least a portion ofa vaporization region 102, in which a feed stream that is delivered as aliquid stream is vaporized prior to being delivered into contact withthe reforming catalyst in hydrogen-producing region 19. In someembodiments, the vaporization region may be contained within thehydrogen-producing region, with the feed stream being vaporized prior tobeing delivered into contact with the reforming catalyst. In someembodiments, the feed stream may be a gaseous stream when introducedinto the internal compartment and therefore may not need to be vaporizedin a vaporization region within the compartment. Also shown in theillustrative example shown in FIG. 2 is a conduit 100 through which thehydrogen gas from the hydrogen-producing region is delivered to hydrogenport 94, which is in fluid communication with the fuel cell stack.

FIG. 2 also illustrates that heated containment structures 70 accordingto the present disclosure also include, or optionally are in thermalcommunication with, a heating assembly 110 that is adapted to heat theinternal compartment to at least a threshold temperature, such as asuitable hydrogen-producing temperature, during periods in which thehydrogen-producing region is not producing hydrogen gas but in which itis desirable to maintain the hydrogen-producing region in a primedoperating state. As discussed, this primed, or thermally primed,operating state may be an operating state in which at least thehydrogen-producing region is maintained at, or within, a suitablehydrogen-producing temperature or range of temperatures. It is withinthe scope of the present disclosure that heating assembly 110 may beconfigured to only heat the internal compartment (and its contents) whenthe hydrogen-producing region is not producing hydrogen gas. However, itis also within the scope of the present disclosure that the heatingassembly may be configured to heat the internal compartment (and itscontents) until the hydrogen-producing region begins producing hydrogengas and/or until the fuel cell stack begins producing a sufficient poweroutput to satisfy the applied load to the fuel cell system. As a furtherillustrative example, the heating assembly may be configured to continueheating the internal compartment and its contents for a selected timeperiod after the above-discussed events occur (or are detected). Asstill a further example, the heating assembly may be adapted to continueto provide heat to the internal compartment (and its contents)regardless of whether the hydrogen-producing region is producinghydrogen gas and/or the fuel cell stack is producing an electriccurrent, such as if the internal compartment, or a selected regionthereof, falls below the threshold temperature (or falls below thistemperature by more than a selected temperature range).

As illustrated in the schematic example shown in FIG. 2, the containmentstructure includes a heating assembly 110 that is adapted to heat theinternal compartment 72 of the containment structure, and accordingly,to heat the hydrogen-producing region and any other structure containedin the internal compartment to the selected threshold temperature. Insolid lines in FIG. 2, heating assembly 110 is illustrated being locatedwithin enclosure 84 and external of the internal compartment 72 of thecontainment structure. As discussed, this configuration is not requiredand it is within the scope of the present disclosure that the heatingassembly may be partially or completely positioned external of enclosure84 and/or within internal compartment 72, as schematically representedin dashed lines in FIG. 2.

A suitable structure for heating assembly 110 is an electrically poweredheater 112, such as resistance heater that is powered by a suitablepower source, such as a battery, an electrical grid, a generator, or anyother suitable power source adapted to provide electrical power to theheater. Heater 112 may, but is not required to, generate a heating fluidstream 116 that is delivered into the internal compartment, such as whenthe heater receives an air stream 118 that is heated and delivered intothe internal compartment. Heater 112 and/or any other suitable heatingassembly 110 may include one or more heating elements, or heat sources,114 that may be positioned in any suitable location relative to theinternal compartment of the containment structure. For example, theheating assembly may include at least one heating element that iswithin, or which extends at least partially within, the internalcompartment. Additionally or alternatively, the heating assembly mayinclude one or more compartments that extend completely, or at leastpartially, within one or more walls 86 of the containment structure.

As a further illustrative, non-exclusive example, heating assembly 110may include a combustion region 120 that generates a heating fluidstream 116 in the form of a combustion exhaust stream that may bedelivered to the internal compartment to heat the compartment andstructures contained herein. The combustion region may be within thecontainment structure, within the internal compartment, or may beexternal the containment structure. In at least this latter example, thecombustion exhaust stream may be delivered to the internal compartmentthrough one or more fluid conduits, such as may extend through at leastone wall of the containment structure to deliver the combustion exhauststream into the internal compartment.

FIG. 3 illustrates an example of a containment structure 70 thatincludes, or is in thermal communication with, a heating assembly 110that includes an electrically powered heater 112. As shown, heater 112is in electrical communication with a power source 130 that is adaptedto provide sufficient power to the heater to enable the heater to heatthe internal compartment to the selected threshold temperature and tothereafter maintain this temperature and/or a suitable temperature rangeof the selected threshold temperature, such as +5° C., ±10° C., or ±25°C. of this temperature. The heating element(s) 114 of the electricalheater may extend in any suitable position relative to the internalcompartment. Illustrative, non-exclusive examples of which includepositions along or within one or more of the walls 86 of the enclosureand/or within internal compartment 72. As illustrated in dashed lines inFIG. 3, the electrical heater may receive an air stream 118, with theheater heating this stream to produce a heating fluid stream that isdelivered into the internal compartment to heat at least thehydrogen-producing region of the thermally primed fuel processingassembly.

FIG. 4 illustrates an example of a containment structure 70 thatincludes, or is in thermal communication with, a heating assembly 110that includes a combustion region 120 that is adapted to receive andcombust a combustible fuel stream 122 in the presence of air, such asfrom an air stream 118, to produce a heating fluid stream 116 in theform of a combustion exhaust stream. Fuel stream 122 may include anysuitable combustible fuel, with illustrative examples including gaseousand liquid fuels. Further illustrative examples include feed stream 16,carbon-containing feedstock 18, hydrogen or other gases produced by thehydrogen-producing region, propane, natural gas, gasoline, kerosene,diesel, and the like. The combustion region may be adapted to receiveand combust a particular fuel or type of fuel. The combustion region mayinclude an igniter, or other suitable ignition source, 124 that isadapted to initiate combustion of the fuel stream, with it being withinthe scope of the present disclosure that the igniter is in electricalcommunication with a power source 130 that is adapted to selectivelyactuate the igniter. In addition to the previously discussed examples ofsuitable power sources, the igniter may be adapted to be powered by aflywheel or ultracapacitor.

As discussed above with respect to FIG. 2, heating assemblies may bepositioned external, within, and/or internal of the enclosure thatdefines the internal compartment of the containment structure.Accordingly, the illustrative examples of electrical heaters andcombustion regions shown in FIGS. 3 and 4 may be implemented at leastpartially, if not completely, external of the enclosure, within theenclosure, or within the internal compartment. As also discussed, atleast when it is located external of the enclosure, the heating assemblymay include at least one fluid conduit to selectively deliver a heatingfluid stream to the internal compartment or otherwise into thermalcommunication with the internal compartment to provide the desiredheating of the compartment and its contents. It is further within thescope of the present disclosure that the internal compartment mayinclude one or more subcompartments, may include one or more heatdeflection structures, thermal baffles or barriers, fans or circulationmembers, and/or other temperature-modulating structures that selectivelydefine regions of higher and lower temperatures within the internalcompartment. These optional temperature-modulating structures areschematically illustrated, individually and in combination, in FIG. 2 at134.

In FIGS. 1-4, thermally primed fuel processing assembly 10 has beendescribed as including at least a hydrogen-producing region 19 that ispositioned within the internal compartment of a heated containmentstructure 70 according to the present disclosure. In each of theseFigures, reference numeral 136 is also presented in dashed lines toindicate that other components of the fuel processing assembly may belocated within the internal compartment and therefore heated andmaintained at a selected threshold temperature and/or within a selectedtemperature range by heating assembly 110. When present in the internalcompartment, these components of the fuel processing assembly should beconfigured to withstand the temperature that is maintained within thecompartment by heating assembly 110. An example of an additionalcomponent of the thermally primed fuel processing that, when present,may be (but is not required to be) housed within compartment 72 is avaporization region, such as schematically illustrated in FIG. 2 at 102.It is within the scope of the present disclosure that vaporizationregion 102, when present, may be otherwise configured and may, in someembodiments, be located within a common shell, or housing, with thehydrogen-producing region in the internal compartment. In FIG. 2, theshell, or housing, that contains the hydrogen-producing region withinthe internal compartment is indicated at 104.

Another example of a component of fuel processing assembly 10 that may(but is not required to) be present in internal compartment 72 is aheating assembly 140 that is adapted to heat at least thehydrogen-producing region when the hydrogen-producing region is in ahydrogen-producing operating state. An illustrative example of such aheating assembly is indicated schematically in FIG. 5. Heating assembly140 may be referred to as a secondary, or active operating state heatingassembly. When present in a particular embodiment of assembly 10, thehydrogen-producing heating assembly is adapted to combust a fuel stream142 to generate a combustion stream 144 to maintain at least thehydrogen-producing region 19 of fuel processing assembly 10 at asuitable hydrogen-producing temperature or range of temperatures. Insuch an embodiment, this secondary heating assembly may be referred toas a burner. Heating assembly 140 may utilize air that is delivered byair stream 118 to support combustion, and may utilize an igniter orother suitable ignition source, such as discussed previously withrespect to combustion region 120. Fuel stream 142 may include anysuitable combustible fuel. While not required to all embodiments, it iswithin the scope of the present disclosure that the fuel stream mayinclude, or even be completely formed from, at least a portion of outputstream 20. It is further which the scope of the present disclosure thatthis gaseous fuel stream may be supplemented with additional fuel thatis delivered to the heating assembly from external the compartment, suchas via a suitable port.

It is within the scope of the present disclosure that thehydrogen-producing region may utilize a process that inherently producessufficiently pure hydrogen gas for use as a fuel stream for fuel cellstack 40. When the output stream contains sufficiently pure hydrogen gasand/or sufficiently low concentrations of one or more non-hydrogencomponents for use as the fuel stream for fuel cell stack 40, producthydrogen stream 14 may be formed directly from output stream 20.However, in many hydrogen-producing processes, output stream 20 will bea mixed gas stream that contains hydrogen gas as a majority componentalong with other gases. Similarly, in many applications, the outputstream 20 may be substantially pure hydrogen gas but still containconcentrations of one or more non-hydrogen components that are harmfulor otherwise undesirable in the application for which the producthydrogen stream is intended to be used.

For example, when stream 14 is intended for use as a fuel stream for afuel cell stack, such as stack 40, compositions that may damage the fuelcell stack, such as carbon monoxide and carbon dioxide, may be removedfrom the hydrogen-rich stream, if necessary. For many fuel cell stacks,such as proton exchange membrane (PEM) and alkaline fuel cell stacks,the concentration of carbon monoxide is preferably less than 10 ppm(parts per million). Preferably, the concentration of carbon monoxide isless than 5 ppm, and even more preferably, less than 1 ppm. Theconcentration of carbon dioxide may be greater than that of carbonmonoxide. For example, concentrations of less than 25% carbon dioxidemay be acceptable in some embodiments. Preferably, the concentration isless than 10%, and even more preferably, less than 1%. While notrequired, especially preferred concentrations are less than 50 ppm. Theacceptable minimum concentrations presented herein are illustrativeexamples, and concentrations other than those presented herein may beused and are within the scope of the present disclosure. For example,particular users or manufacturers may require minimum or maximumconcentration levels or ranges that are different than those identifiedherein.

Accordingly, thermally primed fuel processing assembly 10 may (but isnot required to) further include a purification region 24, in which ahydrogen-rich stream 26 is produced from the output, or mixed gas,stream from hydrogen-producing region 19. Hydrogen-rich stream 26contains at least one of a greater hydrogen concentration than outputstream 20 and a reduced concentration of one or more of the other gasesor impurities that were present in the output stream. In FIG. 6, theillustrative example of a thermally primed fuel processing assemblyshown in FIG. 2 is shown including at least one purification region 24.Purification region 24 is schematically illustrated in FIG. 6, whereoutput, or mixed gas, stream 20 is shown being delivered to an optionalpurification region 24. As shown in FIG. 6, at least a portion ofhydrogen-rich stream 26 forms product hydrogen stream 14. Accordingly,hydrogen-rich stream 26 and product hydrogen stream 14 may be the samestream and have the same compositions and flow rates. However, it isalso within the scope of the present disclosure that some of thepurified hydrogen gas in hydrogen-rich stream 26 may be stored for lateruse, such as in a suitable hydrogen storage assembly, and/or consumed bythe fuel processing assembly.

Purification region 24 may, but is not required to, produce at least onebyproduct stream 28. When present, byproduct stream 28 may be exhausted,sent to a burner assembly or other combustion source (such as ahydrogen-producing heating assembly), used as a heated fluid stream,stored for later use, or otherwise utilized, stored or disposed of. Itis within the scope of the disclosure that byproduct stream 28 may beemitted from the purification region as a continuous stream responsiveto the delivery of output stream 20 to the purification region, orintermittently, such as in a batch process or when the byproduct portionof the output stream is retained at least temporarily in thepurification region.

Purification region 24 includes any suitable device, or combination ofdevices, that are adapted to reduce the concentration of at least onecomponent of output stream 20. In most applications, hydrogen-richstream 26 will have a greater hydrogen concentration than output, ormixed gas, stream 20. However, it is also within the scope of thepresent disclosure that the hydrogen-rich stream will have a reducedconcentration of one or more non-hydrogen components that were presentin output stream 20, yet have the same, or even a reduced overallhydrogen concentration as the output stream. For example, in someapplications where product hydrogen stream 14 may be used, certainimpurities, or non-hydrogen components, are more harmful than others. Asa specific example, in conventional fuel cell systems, carbon monoxidemay damage a fuel cell stack if it is present in even a few parts permillion, while other non-hydrogen components that may be present instream 20, such as water, will not damage the stack even if present inmuch greater concentrations. Therefore, in such an application, asuitable purification region may not increase the overall hydrogenconcentration, but it will reduce the concentration of a non-hydrogencomponent that is harmful, or potentially harmful, to the desiredapplication for the product hydrogen stream.

Illustrative examples of suitable devices for purification region 24include one or more hydrogen-selective membranes 30, chemical carbonmonoxide (or other impurity) removal assemblies 32, and pressure swingadsorption systems 38. It is within the scope of the disclosure thatpurification region 24 may include more than one type of purificationdevice, and that these devices may have the same or different structuresand/or operate by the same or different mechanisms.

Hydrogen-selective membranes 30 are permeable to hydrogen gas, but areat least substantially, if not completely, impermeable to othercomponents of output stream 20. Membranes 30 may be formed of anyhydrogen-permeable material suitable for use in the operatingenvironment and parameters in which purification region 24 is operated.Examples of suitable materials for membranes 30 include palladium andpalladium alloys, and especially thin films of such metals and metalalloys. Palladium alloys have proven particularly effective, especiallypalladium with 35 wt % to 45 wt % copper. A palladium-copper alloy thatcontains approximately 40 wt % copper has proven particularly effective,although other relative concentrations and components may be used withinthe scope of the disclosure.

Hydrogen-selective membranes are typically formed from a thin foil thatis approximately 0.001 inches thick. It is within the scope of thepresent disclosure, however, that the membranes may be formed from otherhydrogen-permeable and/or hydrogen-selective materials, including metalsand metal alloys other than those discussed above as well asnon-metallic materials and compositions, and that the membranes may havethicknesses that are greater or less than discussed above. For example,the membranes may be made thinner, with commensurate increase inhydrogen flux. Examples of suitable mechanisms for reducing thethickness of the membranes include rolling, sputtering and etching. Asuitable etching process is disclosed in U.S. Pat. No. 6,152,995, thecomplete disclosure of which is hereby incorporated by reference for allpurposes. Examples of various membranes, membrane configurations, andmethods for preparing the same are disclosed in U.S. Pat. Nos.6,221,117, 6,319,306, and 6,537,352, the complete disclosures of whichare hereby incorporated by reference for all purposes.

Chemical carbon monoxide removal assemblies 32 are devices thatchemically react carbon monoxide and/or other undesirable components ofstream 20, if present in output stream 20, to form other compositionsthat are not as potentially harmful. Examples of chemical carbonmonoxide removal assemblies include water-gas shift reactors and otherdevices that convert carbon monoxide to carbon dioxide, and methanationcatalyst beds that convert carbon monoxide and hydrogen to methane andwater. It is within the scope of the disclosure that fuel processingassembly 10 may include more than one type and/or number of chemicalremoval assemblies 32.

Pressure swing adsorption (PSA) is a chemical process in which gaseousimpurities are removed from output stream 20 based on the principle thatcertain gases, under the proper conditions of temperature and pressure,will be adsorbed onto an adsorbent material more strongly than othergases. Typically, it is the impurities that are adsorbed and removedfrom output stream 20. The success of using PSA for hydrogenpurification is due to the relatively strong adsorption of commonimpurity gases (such as CO, CO₂, hydrocarbons including CH₄, and N₂) onthe adsorbent material. Hydrogen adsorbs only very weakly and sohydrogen passes through the adsorbent bed while the impurities areretained on the adsorbent material. Impurity gases such as NH₃, H₂S, andH₂O adsorb very strongly on the adsorbent material and are removed fromstream 20 along with other impurities. If the adsorbent material isgoing to be regenerated and these impurities are present in stream 20,purification region 24 preferably includes a suitable device that isadapted to remove these impurities prior to delivery of stream 20 to theadsorbent material because it is more difficult to desorb theseimpurities.

Adsorption of impurity gases occurs at elevated pressure. When thepressure is reduced, the impurities are desorbed from the adsorbentmaterial, thus regenerating the adsorbent material. Typically, PSA is acyclic process and requires at least two beds for continuous (as opposedto batch) operation. Examples of suitable adsorbent materials that maybe used in adsorbent beds are activated carbon and zeolites, especially5 Å (5 angstrom) zeolites. The adsorbent material is commonly in theform of pellets and it is placed in a cylindrical pressure vesselutilizing a conventional packed-bed configuration. Other suitableadsorbent material compositions, forms, and configurations may be used.

PSA system 38 also provides an example of a device for use inpurification region 24 in which the byproducts, or removed components,are not directly exhausted from the region as a gas stream concurrentlywith the purification of the output stream. Instead, these byproductcomponents are removed when the adsorbent material is regenerated orotherwise removed from the purification region.

In the illustrative, non-exclusive embodiment shown in FIG. 6,purification region 24 is shown in solid lines within internalcompartment 72 and as a separate structure from the housing 104 thatcontains hydrogen-producing region 19. It is within the scope of thedisclosure that housing 104 may additionally or alternatively include apurification region 24 in addition to hydrogen-producing region 19, withthe purification region(s) being adapted to receive the mixed gas, orreformate, stream produced in the hydrogen-producing region. It is alsowithin the scope of the present disclosure that the fuel processingassembly may include a purification region 24 that is external of thecontainment structure's enclosure, such as indicated in dash-dot linesin FIG. 6. Any of the thermally primed fuel processing assembliesdescribed, illustrated and/or incorporated herein may be, but are notrequired to be, implemented with one or more of the purification regionsdescribed, illustrated, and/or incorporated herein.

In the context of a fuel processor, or fuel processing assembly, that isadapted to produce a product hydrogen stream that will be used as afeed, or fuel, stream for a fuel cell stack, the fuel processorpreferably is adapted to produce substantially pure hydrogen gas, andeven more preferably, the fuel processor is adapted to produce purehydrogen gas. For the purposes of the present disclosure, substantiallypure hydrogen gas is greater than 90% pure, preferably greater than 95%pure, more preferably greater than 99% pure, and even more preferablygreater than 99.5% pure. Suitable fuel processors for producing streamsof at least substantially pure hydrogen gas are disclosed in U.S. Pat.Nos. 6,319,306, 6,221,117, 5,997,594, 5,861,137, pending U.S. patentapplication Ser. No. 09/802,361, which was filed on Mar. 8, 2001 and isentitled “Fuel Processor and Systems and Devices Containing the Same,”and U.S. patent application Ser. No. 10/407,500, which was filed on Apr.4, 2003, is entitled “Steam Reforming Fuel Processor,” and which claimspriority to U.S. Provisional Patent Application Ser. No. 60/372,258. Thecomplete disclosures of the above-identified patents and patentapplications are hereby incorporated by reference for all purposes.

FIG. 7 illustrates another example of a fuel cell system 42 thatincludes a thermally primed fuel processing assembly 10 according to thepresent disclosure. FIG. 7 is intended to illustrate additionalcomponents that may, but are not required in all embodiments, beincluded in system 42 and/or assembly 10. In other words, it is withinthe scope of the present disclosure that thermally primed fuelprocessing assemblies and fuel cell systems containing the same mayinclude additional components besides those described and/or illustratedherein, such as one or more suitable, controllers, flow regulatingdevices, heat exchangers, heating/cooling assemblies, fuel/feedsupplies, hydrogen storage devices, energy storage devices, reservoirs,filters, and the like.

Fuel cell stack 40 may receive all of product hydrogen stream 14. Someor all of stream 14 may additionally, or alternatively, be delivered,via a suitable conduit, for use in another hydrogen-consuming process,burned for fuel or heat, or stored for later use. As an illustrativeexample, a hydrogen storage device 50 is shown in FIG. 7. Device 50 isadapted to store at least a portion of product hydrogen stream 14. Forexample, when the demand for hydrogen gas by stack 40 is less than thehydrogen output of fuel processor 12, the excess hydrogen gas may bestored in device 50. Illustrative examples of suitable hydrogen storagedevices include hydride beds and pressurized tanks. Although notrequired, a benefit of fuel processing assembly 10 or fuel cell system42 including a supply of stored hydrogen gas is that this supply may beused to satisfy the hydrogen requirements of stack 40, or the otherapplication for which stream 14 is used, in situations when thermallyprimed fuel processor 12 is not able to meet these hydrogen demands.Examples of these situations include when the fuel processor is offlinefor maintenance or repair, and when the fuel cell stack or applicationis demanding a greater flow rate of hydrogen gas than the maximumavailable production from the fuel processor. Additionally oralternatively, the stored hydrogen may also be used as a combustiblefuel stream to heat the fuel processing assembly or fuel cell system.Fuel processing assemblies that are not directly associated with a fuelcell stack may still include at least one hydrogen storage device,thereby enabling the product hydrogen streams from these fuel processingassemblies to also be stored for later use.

Thermally primed fuel cell system 42 may also include a battery or othersuitable energy storage device 52 that is adapted to store the electricpotential, or power output, produced by stack 40 and to utilize thisstored potential to provide a power source (such as one or more of thepreviously described power sources 130). For example, device 52 may beadapted to provide power to one or more of an igniter, pump (such as tosupply feed stream 16), blower or other air propulsion device (such asto deliver air stream 118), sensor, controller, flow-regulating valve,and the like. Device 52 may be a rechargeable device, and fuel cellsystem 42 may include a charging assembly that is adapted to rechargethe device. It is also within the scope of the present disclosure thatdevice 52 may be present in system 42 but may not be adapted to berecharged by system 42. Similar to the above discussion regarding excesshydrogen gas, fuel cell stack 40 may produce a power output in excess ofthat necessary to satisfy the load exerted, or applied, by device 46,including the load required to power fuel cell system 42. In furthersimilarity to the above discussion of excess hydrogen gas, this excesspower output may be used in other applications outside of the fuel cellsystem and/or stored for later use by the fuel cell system. For example,the battery or other storage device may provide power for use by system42 during periods in which the system is not producing electricityand/or hydrogen gas.

When fuel cell system 42 includes a hydrogen storage device 50, thehydrogen storage device may be designed, sized, or otherwise adapted tonot be able to satisfy the hydrogen demands of the fuel cell stackduring a time period that is equal to the time period in which it wouldtake the fuel cell system to start up from an unheated operating state(i.e., if the system was implemented without a thermally primed fuelprocessing assembly). This response time may be referred to as a startup response time, in that it includes the time required to heat at leastthe hydrogen-producing region to a suitable hydrogen-producingtemperature. This start up response time is contrasted with the timerequired to produce hydrogen gas from the thermally primed fuelprocessing assembly that has been maintained at a suitablehydrogen-producing temperature, and then to generate a power outputtherefrom. This response time may be referred to a thermally biasedresponse time.

Therefore, while not required, the fuel cell system may include ahydrogen storage device that has insufficient capacity, even when fullycharged, to provide sufficient amounts of hydrogen gas to provide thehydrogen gas required by the fuel cell stack to satisfy the applied loadthereto during a time period that is equal to the time that wouldotherwise be required to start up the fuel cell system from an off, orunheated, operating state. As further illustrative examples, the maximumcapacity of the hydrogen-storage device may be selected to be less than75%, less than 50% or even less then 25% of this potential hydrogendemand. Expressed in slightly different terms, during a time period thatcorresponds to the time it would take to start up the fuel cell stackfrom an unheated operating state (i.e., if the thermally primed fuelprocessor assembly was not present or operational), the fuel cell stackmay require a volume of hydrogen gas to generate a sufficient poweroutput to satisfy the applied load thereto, with this volume exceedingthe capacity of the hydrogen storage device, and optionally exceedingthe capacity of the hydrogen storage device by at least 25%, 50%, 75%,or even 100% of its capacity.

Similarly, when fuel cell system 42 includes an energy storage device52, such as a battery, capacitor or ultracapacitor, flywheel, or thelike, this device may have a maximum charge that is less than the poweroutput that would be required to satisfy the applied load to the fuelcell stack during a time period that corresponds to the time that wouldbe required to startup the fuel cell system from an unheated, offoperating state (i.e., if the thermally primed fuel processing assemblywas not present). It is within the scope of the present disclosure thatthis maximum charge may be less than the required power output by atleast 25%, 50%, 75%, or more. Expressed in slightly different terms,during a time period that corresponds to the time it would take to startup the fuel cell stack from an unheated (off and/or unprimed) operatingstate (i.e., if the thermally primed fuel processing assembly was notpresent), the energy-consuming device may demand, or require, a poweroutput that exceeds the maximum (i.e., fully charged) capacity of theenergy-storage device.

This intentional undersizing of devices 50 and/or 52 is not required,especially since these components are not required to all embodiments.However, the above discussion demonstrates that it is within the scopeof the present disclosure to include a hydrogen storage device and/orenergy storage device while still requiring the heated containmentassembly for the system to be properly operational. A relatedconsideration is the cost and/or space required for these components ifthey were sized to provide a fuel cell system that did not include aheated containment structure according to the present disclosure.

In FIG. 7, optional flow-regulating structures are generally indicatedat 54 and schematically represent any suitable manifolds, valves,controllers, switches and the like for selectively delivering hydrogengas and the fuel cell stack's power output to device 50 and battery 52,respectively, and to draw the stored hydrogen and stored power outputtherefrom. Also shown in FIG. 7 is an optional, and schematicallyillustrated, example of a power management module 56 that is adapted toregulate the power output from the fuel cell stack, such as to filter orotherwise normalize the power output, to convert the power output to ahigher or lower voltage, to convert the power output from a DC poweroutput to an AC power output, etc.

Thermally primed fuel processing assemblies, and fuel cell systemsincorporating the same, may also include or be in communication with acontroller that is adapted to selectively control the operation of theassembly/system by sending suitable command signals and/or to monitorthe operation of the assembly/system responsive to input from varioussensors. A controller is indicated in dash-dot lines at 58 in FIG. 7 asbeing in communication with energy-storage device 52 (and/or powersource 130) to indicate that the controller may be adapted to be poweredthereby. It is also within the scope of the present disclosure that thecontroller, when present, is powered by another suitable power source.The controller may be a computerized, or computer-implemented controllerand in some embodiments may include software and hardware components.The controller may be a dedicated controller, in that it is primarilyadapted to monitor and/or control the operation of the fuel cell systemor fuel processing assembly. It is also within the scope of the presentdisclosure that the controller, when present, may be adapted to performother functions.

In FIG. 8, a thermally primed fuel cell system 42 (i.e., a fuel cellsystem that includes a thermally primed fuel processing assembly 10)according to the present disclosure is shown being adapted to providebackup power to an energy-consuming device 46 that is adapted to bepowered by a primary power source 200. In other words, when the primarypower source is operational, it satisfies the load applied byenergy-consuming device 46. While primary power source 200 isoperational and available to satisfy the applied load fromenergy-consuming device 46, the heated containment structure ofthermally primed fuel processing assembly 10 may be operational tomaintain at least the hydrogen-producing region 19 of the fuel processorat a threshold hydrogen-producing temperature range and/or within athreshold hydrogen-producing temperature range, such as those describedand/or incorporated herein. In such a configuration, fuel cell system 42is configured to provide backup, or supplemental, power to theenergy-consuming device, such as when the primary power source is notoperational or is otherwise not available or able to satisfy the appliedload from the energy-consuming device. In FIG. 8, only portions ofsystem 42 are shown, and it is within the scope of the presentdisclosure that system 42 may include any of the components,subcomponents, and/or variants described, illustrated and/orincorporated herein.

When configured to provide backup power to an energy-consuming device46, system 42 may be configured to detect the operational state of theprimary power source via any suitable mechanism and/or may be adapted toinitiate the production of hydrogen gas (and thereby initiate thegeneration of power output 41) responsive to detecting an applied loadto the fuel cell system from the energy-consuming device. When system 42includes, or is in communication with a controller, the controller mayinclude at least one sensor that is adapted to detect whether a load isbeing applied to the thermally primed hydrogen-producing fuel cellsystem from the energy-consuming device, and/or whether the primarypower source is providing any (or sufficient) power to theenergy-consuming device. Responsive at least in part to this detection,the controller may initiate the production of hydrogen gas by sendingone or more suitable command signals to the feedstock delivery system tocause stream(s) 16 to be delivered to the hydrogen-producing region ofthe fuel processing assembly. The controller may be adapted to performvarious diagnostics, or system integrity checks responsive to thedetection that system 42 is needed to provide a power output to satisfyan applied load from the energy-consuming device. As discussed, thecontroller may be a computerized, or computer-implemented controllerthat is adapted to perform various control and/or monitoring functionsand/or which may include hardware and software components, may include amicroprocessor, and/or may include a digital or analog circuit. Thecontroller, when present, may also simply include a sensor or detectorthat is adapted to send a command signal to feedstock delivery system 22responsive to detecting that there is a need for system 42 to beingproducing a power output.

As indicated in FIG. 8, it is within the scope of the present disclosurethat at least the heating assembly 110 of, or associated with, theheated containment structure may be adapted to be powered by the primarypower source when the primary power source is available to satisfy theapplied load of the energy-consuming device. Accordingly, when theprimary power source is operational, it may be configured to supply theapplied load of the energy-consuming device, while also providing powerto at least the heating assembly of the thermally primed fuel processingsystem of fuel cell system 42. In such a configuration, the fuel cellsystem may be maintained in its “primed” operational state, in which atleast the hydrogen-producing region thereof is maintained at a suitabletemperature for producing hydrogen gas therein responsive to thedelivery of a suitable feed stream(s) thereto. However, because thepower requirements of the fuel cell system are satisfied by the primarypower source while the primary power source is operational, the fuelcell system does not need to generate a sufficient, or even any, poweroutput while in its primed operational state. Similarly, the fuelprocessing assembly may not be generating any hydrogen gas while in thisoperational state, even though it is being maintained at a suitabletemperature, or within a suitable temperature range, for generatinghydrogen gas.

When, and if, the primary power source fails, is offline, or otherwiseis unable to satisfy the applied load of the energy-consuming device,the thermally primed fuel cell system is able to generate a power outputto satisfy this applied load. Furthermore, because the fuel processingassembly was maintained at a suitable temperature (or temperature range)for generating hydrogen gas, the time required to begin generating therequired power output will be considerably less than if the fuelprocessing assembly was instead maintained at an unheated, or off,operational state. For example, the thermally primed fuel cell systemmay be able to satisfy the applied load in less then a few minutes, suchas less then three minutes, less than two minutes, less then one minute,or even less than forty-five seconds, inclusive of any diagnostics orother self-checks performed by a controller of the system. Expressed inslightly different terms, thermally biased hydrogen-producing fuel cellsystems may have a thermally biased response time to begin generating apower output from hydrogen gas produced in the system, with thisresponse time being less than a few minutes, less than two minutes, lessthan one minute, less than forty-five seconds, etc. This response timewill be much shorter than a comparative start up response time if thehydrogen-producing fuel cell system was not a thermally biasedhydrogen-producing fuel cell system.

As discussed above, thermally primed fuel cell systems according to thepresent disclosure may include a hydrogen-storage device and/or anenergy-storage device that is undersized for a fuel cell system thatdoes not include a thermally primed fuel processing assembly, such as anassembly that includes a heated containment structure according to thepresent disclosure. However, the hydrogen storage device and/orenergy-storage device may be sized to provide the required hydrogen gasand/or power output during the much shorter time period that elapses forthe thermally primed fuel cell system to begin generating a sufficientpower output to satisfy the applied load of energy-consuming device 46.For example, this may enable the fuel cell system to provide anuninterruptible backup power supply (UPS) for the energy-consumingdevice.

INDUSTRIAL APPLICABILITY

Thermally primed fuel processing assemblies and hydrogen-producing fuelcell systems containing the same are applicable to the fuel processing,fuel cell and other industries in which hydrogen gas is produced, and inthe case of fuel cell systems, consumed by a fuel cell stack to producean electric current.

It is believed that the disclosure set forth above encompasses multipledistinct inventions with independent utility. While each of theseinventions has been disclosed in its preferred form, the specificembodiments thereof as disclosed and illustrated herein are not to beconsidered in a limiting sense as numerous variations are possible. Thesubject matter of the inventions includes all novel and non-obviouscombinations and subcombinations of the various elements, features,functions and/or properties disclosed herein. Similarly, where theclaims recite “a” or “a first” element or the equivalent thereof, suchclaims should be understood to include incorporation of one or more suchelements, neither requiring nor excluding two or more such elements.

It is believed that the following claims particularly point out certaincombinations and subcombinations that are directed to one of thedisclosed inventions and are novel and non-obvious. Inventions embodiedin other combinations and subcombinations of features, functions,elements and/or properties may be claimed through amendment of thepresent claims or presentation of new claims in this or a relatedapplication. Such amended or new claims, whether they are directed to adifferent invention or directed to the same invention, whetherdifferent, broader, narrower, or equal in scope to the original claims,are also regarded as included within the subject matter of theinventions of the present disclosure.

1. A thermally primed hydrogen-producing fuel cell system, comprising: afuel processing assembly comprising a hydrogen-producing region thatcontains a reforming catalyst, wherein the hydrogen-producing region isadapted to receive a feed stream containing at least a carbon-containingfeedstock and water and to produce from the feed stream a reformatestream containing hydrogen gas as a majority component; a fuel cellstack adapted to receive an oxidant and a fuel stream containinghydrogen gas produced in the hydrogen-producing region, wherein the fuelcell stack is further adapted to generate a power output from the fuelstream and the oxidant; a containment structure including an enclosurethat defines an internal compartment containing at least thehydrogen-producing region of the fuel processing assembly; and a heatingassembly adapted to heat and maintain at least the internal compartmentof the containment structure at or above a threshold temperature duringperiods in which the fuel cell system is not producing the power outputand the fuel processing assembly is not producing the reformate stream.2. The fuel cell system of claim 1, wherein the fuel cell stack isadapted to supply the power output to satisfy an applied load from anenergy-consuming device when a primary power source that is normallyadapted to satisfy the applied load is not providing a power output tosatisfy the applied load.
 3. The fuel cell system of claim 2, whereinthe heating assembly is adapted to be powered by the primary powersource when the primary power source is configured to satisfy theapplied load from the energy-consuming device.
 4. The fuel cell systemof claim 2, wherein the primary power source includes an electricalgrid.
 5. The fuel cell system of claim 2, wherein the heating assemblyis adapted to stop heating the internal compartment when the fuelprocessing assembly is producing hydrogen gas.
 6. The fuel cell systemof claim 5, wherein the fuel processing assembly further comprises asecond heating assembly, wherein the second heating assembly ispositioned within the enclosure and is adapted to receive and combust agaseous fuel stream to provide heat to at least the hydrogen-producingregion of the fuel processing assembly when the fuel processing assemblyis producing hydrogen gas.
 7. The fuel cell system of claim 1, whereinthe hydrogen-producing region is adapted to produce hydrogen gas fromthe feed stream, if delivered thereto, when the hydrogen-producingregion is at the threshold temperature.
 8. The fuel cell system of claim7, wherein the carbon-containing feedstock is methanol and the thresholdtemperature is at least 350° C.
 9. The fuel cell system of claim 7,wherein the carbon-containing feedstock is a hydrocarbon and thethreshold temperature is at least 700° C.
 10. The fuel cell system ofclaim 1, wherein the enclosure is an insulated enclosure having aninternal surface, which defines at least in part the internalcompartment, and an exterior surface, and further wherein the enclosureis adapted to maintain the exterior surface at a temperature that isless than 100° C. when the threshold temperature is at least 350° C. 11.The fuel cell system of claim 10, wherein the enclosure is adapted tomaintain the exterior surface at a temperature that is less than 50° C.when the threshold temperature is at least 350° C.
 12. The fuel cellsystem of claim 1, wherein the fuel processing assembly furthercomprises at least one purification region adapted to receive at least aportion of the reformate stream and to produce a product hydrogen streamhaving at least one of a greater concentration of hydrogen gas and alower concentration of at least one of the other gases present in thereformate stream.
 13. The fuel cell system of claim 12, wherein the fuelprocessing assembly includes at least one purification region within theinternal compartment.
 14. The fuel cell system of claim 12, wherein thefuel processing assembly includes at least one purification regionexternal the enclosure.
 15. The fuel cell system of claim 1, wherein thefuel cell system further includes an energy storage device adapted tosatisfy an applied load from at least one of the fuel cell system and anenergy-consuming device.
 16. The fuel cell system of claim 15, whereinthe fuel cell system has a thermally primed response time to producehydrogen gas with the fuel processing assembly when the fuel processingassembly has been heated to at least the threshold temperature by theheating assembly and to generate the power output from hydrogen gasproduced by the fuel processing assembly, wherein the energy storagedevice has a maximum charge that is adapted to satisfy an applied loadfor a time period, and further wherein the time period is greater thanthe thermally primed response time.
 17. The fuel cell system of claim16, wherein the fuel cell system has a startup response time to beginproducing the power output from hydrogen gas when the fuel processingassembly has not been heated to the threshold temperature by the heatingassembly, and further wherein the time period is less than the startupresponse time.
 18. A thermally primed hydrogen-producing fuel cellsystem, comprising: a fuel processing assembly comprising ahydrogen-producing region that contains a reforming catalyst, whereinthe hydrogen-producing region is adapted to receive a feed streamcontaining at least a carbon-containing feedstock and water and toproduce from the feed stream a reformate stream containing hydrogen gasas a majority component; a purification region adapted to receive atleast a portion of the reformate stream and to separate the portion intoa product hydrogen stream containing greater hydrogen purity than thereformate stream, and a byproduct stream; a fuel cell stack adapted toreceive an oxidant and a fuel stream containing hydrogen gas produced inthe hydrogen-producing region, wherein the fuel cell stack is furtheradapted to generate a power output from the fuel stream and the oxidant;a containment structure including an insulated enclosure that defines aninternal compartment containing at least the hydrogen-producing regionand the purification region of the fuel processing assembly; and aheating assembly adapted to heat and maintain at least the internalcompartment of the containment structure at or above a thresholdtemperature of at least 350° C. during periods in which the fuel cellsystem is not producing the power output and the fuel processingassembly is not producing the reformate stream, wherein the heatingassembly is not powered by the fuel cell system at least when the fuelcell system is not producing the power output.
 19. The fuel cell systemof claim 18, wherein the heating assembly is an electrically poweredheating assembly.
 20. The fuel cell system of claim 18, wherein the fuelcell system further comprises a second heating assembly that is adaptedto receive and combust at least the byproduct stream, and furtherwherein the second heating assembly is contained within the compartment.21. A method for using a thermally primed hydrogen-producing fuel cellsystem, which includes at least a hydrogen-producing fuel processingassembly and a fuel cell stack, to supplement a primary power sourceadapted to satisfy an applied load from an energy-consuming device, themethod comprising: heating at least a hydrogen-producing region of afuel processing assembly to at least a threshold temperature at whichthe hydrogen-producing region is adapted to produce a mixed gas streamcontaining hydrogen gas as a majority component from a feed streamcontaining water and a carbon-containing feedstock; maintaining thehydrogen-producing region at or above the threshold temperature duringperiods in which the hydrogen-producing region is not producing hydrogengas; delivering at least water and a carbon-containing feedstock to thehydrogen-producing region during a transition period in which there is ademand for a power output from the fuel cell system to satisfy anapplied load; producing hydrogen gas in the hydrogen-producing region;and generating the power output with the fuel cell stack from oxidantand hydrogen gas produced in the hydrogen-producing region.
 22. Themethod of claim 21, wherein the heating and maintaining is performed bya heating assembly that is adapted to heat at least thehydrogen-producing region of the fuel processing assembly.
 23. Themethod of claim 22, wherein the heating assembly is an electricallypowered heating assembly that is adapted to be powered by the primarypower source.
 24. The method of claim 22, wherein the method furtherincludes stopping the maintaining by the heating assembly prior to thegenerating step.
 25. The method of claim 21, wherein at least one of theheating and the maintaining steps includes powering a heating assemblywith the primary power source to generate heat to heat thehydrogen-producing region.
 26. The method of claim 21, wherein at leastthe hydrogen-producing region of the fuel processing assembly iscontained in an internal compartment of an enclosure, and furtherwherein the heating and maintaining steps include utilizing a heatingassembly to heat the internal compartment to at least a thresholdtemperature.
 27. The method of claim 26, wherein the thresholdtemperature corresponds to a temperature at which the hydrogen-producingregion is adapted to produce, from water and at least onecarbon-containing feedstock, a stream containing hydrogen gas as amajority component.
 28. The method of claim 21, further comprisingdetecting when the primary power source is not able to satisfy theapplied load from the energy-consuming device and initiating thedelivering step responsive at least in part thereto.
 29. The method ofclaim 28, wherein upon the occurrence of the detecting step, the methodis adapted to complete the delivering and producing step and to initiatethe generating step in less than one minute.